ZBrushCentral

Heavy lines on mesh

Hello,
New user here, for some reason I am getting heavy lines on my mesh which get more defined if I sculpt on it. See images below

What did I do to cause this?
Any help would be appreciated

Attachments

zbrush1.jpg

zbrush-2.jpg

What brushes are you using, and at what intensity? Also have you tried smoothing the strokes?